1. Field
Example embodiments relates to a distance measuring sensor including a double transfer gate, and a three dimensional color image sensor including the distance measuring sensor.
2. Description of the Related Art
Photogate depth sensors may measure a distance to an object by detecting reflected light from the object. The photogate depth sensors may irradiate light onto an object, measure a delay time by measuring light reflected from the object, and calculate a distance from the object according to the measured delay time.
Color image sensors are photoelectric conversion devices that may convert light into an electric signal. Conventional image sensors may include a plurality of unit pixels arranged in a matrix on a semiconductor substrate. Each unit pixel may include a photodiode and transistors. The photodiode may generate and store a photo-charge by detecting light from the outside, and the transistors may output an electric signal according to the charge amount of the generated photo-charge.
Complementary metal oxide semiconductor (CMOS) image sensors may include a photodiode that receives and stores an optical signal, and realizes an image by using a control device that controls or processes the optical signal. Since the control device may be manufactured by using a CMOS manufacturing technology, the CMOS image sensors may have simple manufacturing processes, and moreover, may be manufactured as one chip including the control device and the photodiode.
Three dimensional color image sensors may realize a three dimensional color image of an object by measuring colors of the object and a distance to the object.
A conventional distance measuring sensor may include a double photogate on a light incidence surface, and thus the light amount may be reduced while passing through the double photogate or a light sensing region may be reduced due to the double photogate, thereby reducing a distance measuring sensitivity. Also, the material of the double photogate may be limited to polysilicon, which is a light-transmissive material.